JP3300352B2 - Method and apparatus for applying a liquid material, especially a hot melt, to a substrate by a sequentially operating applicator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a control valve for a liquid material which can be controlled to open and close, particularly a hot melt, connected to a material supply unit, and is moved relative to the coating machine by the coating machine. The present invention relates to a method for subdividing a material pattern into a pattern portion having a small gap in the moving direction when applying the material pattern to an object to be coated, and an apparatus for performing the method.

A method of applying a liquid material, particularly a hot melt, to an object to be coated by an applicator using a control valve capable of controlling opening and closing is a technique known per se.

As long as the speed of the substrate with respect to the coating machine is kept below a certain value and the gap between the pattern portions is not too small, no special problem occurs. However, especially in the case of using an air-operated valve, a large air supply unit and a discharge duct are provided for control to prepare a pattern with a sharp contour, that is, a pattern without irregularities in the contour. Air needs to be supplied and exhausted in a short time.

However, the situation changes when the relative speed increases and the gap between the pattern portions must be reduced. In such a case, the time between the rapid closing of the valve and the subsequent rapid opening thereof becomes extremely short, so that good results cannot be obtained. This problem is particularly encountered when using air-operated valves. This pneumatically operated valve requires a considerable amount of air to be supplied or exhausted through a large duct for rapid opening and closing of the valve.

An object of the present invention is to solve the above-mentioned problem.
According to the invention, at least two control valves connected to the material supply and opened and closed sequentially are used for this purpose.

For example, when two control valves are provided,
The first of these two control valves is closed at the end of the operating cycle by rapid exhaust of control air, but the material can be re-supplied immediately by a subsequent opening operation. If not, the function of the first valve is taken over by a second valve, which is opened at the correct time. During this period of opening of the second valve, the first valve can recover to the normal state, so that the first valve
When these valves are closed, they are ready for the next operation cycle. Thus, high-speed operation without malfunction is achieved.

Of course, the principles of the present invention can be applied to systems with more than two, for example three or even four, control valves that are controlled sequentially.

It is also possible to divide these valves into two or more sets, in which case each set includes at least two valves,
These sets are opened and closed sequentially. For example, 4 divided into 2 or 3 sets each consisting of 2 or 3 valves
One or six control valves can be associated with the applicator, which ensures good results even with relatively long nozzles of the applicator.

An apparatus for performing the method according to the invention is described in claim 4
Defined in paragraphs 7 to 7.

Incidentally, an applicator equipped with two control valves is disclosed in U.S. Pat.
No. 169, however, in this known device, the principle of the invention is not known from the above-mentioned publication, since the two control valves are opened and closed simultaneously.

 The present invention will be described with reference to the following drawings.

1a, 1b and 1c show examples of patterns of a liquid material, particularly a hot melt, applied to an object to be coated.

FIG. 2 schematically shows an apparatus in which the method according to the invention can be used.

FIG. 3 shows a time chart for opening and closing the valves used in the device according to FIG.

FIG. 4 is a perspective view of an applicator suitable for using the method according to the invention.

FIG. 5 is a schematic diagram showing a device in which a plurality of valves are subdivided into two sets of three valves each.

In FIG.1a, reference numeral 2a denotes the outlet nozzle of the applicator, which is known per se and whose detailed structure is not shown,
The outflow nozzle applies a strip of liquid material, particularly hot melt, to the substrate in a fixed pattern. The substrate is the face of this drawing, and the three strips shown are indicated by reference numerals 4a-4c. The substrate should move below the outflow nozzle 2a in the direction of arrow 6, for example at a speed of 100 m / min, i.e. 1,670 mm / sec, while the distance d between each material strip is 3 mm It can be. This means that the elapsed time between shutting off the supply of material to the applicator opening 2 and resuming said supply must be only 1.8 milliseconds. The length l ₁ is about 30 mm, which corresponds to the application time of about 20 milliseconds.

FIG. 1b shows the case where the nozzle 2b has to apply a narrow strip of material indicated by 8a to 8e to the workpiece.
In this case, the distance l ₂ between longitudinal edges of each material strip is equal to the spacing d ₂ of the material pieces fine each. Thus, both the material supply period and the material supply interruption period are only 1.8 milliseconds.

The last Figure 1c, a regular pattern of material 12a ‥‥ 12d of a plurality of columns, such as the length l ₃ and distance d ₃ is each about 3 mm, a single applicator nozzle having a plurality of obstacles 10a~10c FIG. 2c illustrates a method of applying to an object to be coated. Also in this case, the material supply time and the material supply interruption time are set to 1.8 milliseconds.

This cannot be achieved with devices according to the prior art, but can be achieved with the measures according to the invention. The principle of the present invention will be described with reference to FIGS.

FIG. 2 schematically shows the coating machine 14.
The fourteen nozzle openings 16 are arranged at a small distance above the workpiece 18 and the workpiece 18 moves relative to the nozzle openings 16 and at right angles to the drawing. The inner space 20 of the applicator nozzle 22 is connected to a common material supply line 28 by air-controlled control valves 24 and 26, and the material, especially hot melt, is supplied under pressure from a supply source 32 by a pressure pump 30. It is supplied via line 28. The control valve 24 is pneumatically controlled by a shuttle valve 36 via a line 34, the connection 36 a of which communicates with a pressure medium source 40 via a line 38. Also, the connecting portion 36 of the shuttle valve 36
b can be open to the atmosphere or connected to an air vent. Control valve 26 is connected to shuttle valve 44 via line 42
, The connection 44a of this shuttle valve 44 communicates with the line 38 and thus with the pressure medium source 40.
On the other hand, the connecting portion 44b of the shuttle valve 44 is open to the atmosphere.

Shuttle valves 36 and 44 are connected to control lines (4
6,48), which is electrically controlled by a central control unit 50, the central control unit 50 comprising shuttle valves 36,44
Supplies current pulses necessary for these controls.

FIG. 3 shows the above control pulse as a function of time, in which line 3a relates to the current pulse supplied to shuttle valve 36 and line 3b represents the current pulse supplied to shuttle valve 44. About the pulse,
Line 3c is the time axis. While a current pulse is applied to the shuttle valve 36 or 44, the shuttle valve will
It is controlled to open 26. This chart relates to the state schematically shown in FIG. 1a.

Thus the control valve 24 is opened at time t _1, is closed at time t _2, thereby, the time interval [Delta] T ₁ corresponds to the length l ₁ of the material strip 4a in Figure 1a. During the above-mentioned time interval, which can for example be set to 20 milliseconds, the material flows out of the nozzle opening 2a.

after t ₂ [Delta] T _2, for example, the time from t ₂ is after 1.8 ms t
_{At 3} , the control valve 26 is opened. This opening is continued from t ₃ to [Delta] T ₁ after time point t ₄ of during this period, the material is supplied to the discharge opening 16 of the nozzle 22 by the control valve 26, the material strip 4b. Subsequent material supply is performed again by the control valve 24. Time t ₆ or control valve 24 is opened at time t ₅
Keep open until. Thereafter, the control valve 26 takes over the operation of the control valve 24.

As is clear from the above, when the applicator nozzle performs the above-described operation method, the two air-operated control valves 2
4,26 have sufficient time after closing to enter a stable closed state in which the transition phenomena have disappeared, and these valves are ready to be opened again for reliable material supply.

FIG. 4 shows a unit structure made by combining the control valves 24 and 26 with the coating machine nozzle 22. Note that the various supply and control lines are not shown in this figure.

Finally, FIG. 5 schematically shows a method of uniformly distributing the material by using three or more control valves when a relatively long applicator nozzle 60 is installed above the workpiece 62. is there. In the illustrated example, the six control valves are divided into two sets indicated by 64a, 64b, 64c and 66a, 66b, 66c, respectively. These control valves 64a, 64b, 64c share a common control line 6
8, and the control valves 66a, 66b, 66c are simultaneously operated by the control line 70. The control line 68 corresponds to, for example, the control line 34 of FIG. 2, and the control line 70 corresponds to the control line 42 of FIG. Line 68 is a shuttle valve 72
The function of shuttle valve 72 corresponds to the function of shuttle valve 36 of FIG. 2, while line 70 is connected to shuttle valve 74 and the function of shuttle valve 74 is
It supports 44 functions. Other connections of the shuttle valve described above are not shown to avoid complications.

The length l ₂ , l ₃ of the material strip is the length l of the material strip shown in FIG.
If it is much smaller than _1, the duration ΔT ₁ of each control pulse will be correspondingly shorter, but still be long enough to ensure good functioning.

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-63-54973 (JP, A) JP-A-62-266157 (JP, A) JP-A-59-203669 (JP, A) JP-A-63-54963 106379 (JP, A) JP-A-64-15172 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05C 5/00-5/02 B05C 11/10 B05D 1/26

Claims (7)

(57) [Claims] A control valve for a liquid which can be controlled to open and close, particularly for a hot melt, connected to a material supply unit is used to apply a coating material which is moved sequentially by an application machine to a coating machine. A method of applying a material pattern, wherein the material pattern is subdivided into pattern portions having a slight space in the movement direction, wherein at least two of the material patterns are connected to the material supply unit and sequentially opened and closed. A method comprising using a plurality of control valves. 2. The method as claimed in claim 1, wherein a pneumatically controlled control valve is used. 3. At least two sets of control valves are used for each applicator, each set comprising at least two control valves,
3. The method according to claim 1, wherein the at least two sets are opened and closed sequentially. 4. An applicator which is supplied with material by at least two control valves which can be controlled to open and close connected to a material supply section, and control means for sequentially opening and closing the respective valves. Apparatus for implementing the method according to claims 1 to 3, characterized in that: 5. Apparatus according to claim 4, wherein said control valve is connected to one common outlet duct. 6. Apparatus according to claim 4, wherein said control valve is an air-operated valve. 7. The applicator cooperates with at least two sets of control valves, each set of the two sets of control valves comprising at least two valves, and wherein the control means comprises a respective one of the respective sets. Apparatus according to claims 4 to 6, characterized in that the valve is configured to open and close sequentially.